Orthogonal Locality Preserving model reduction and flow separation control for incompressible Navier Stokes equations

2017 ◽  
Author(s):  
Samir Sahyoun ◽  
Seddik M. Djouadi
Keyword(s):  
Model Reduction ◽  
Flow Separation ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Separation Control ◽  
Navier Stokes Equations ◽  
Flow Separation Control ◽  
Locality Preserving

scholarly journals Numerical Investigation of Jet Angle Effect on Airfoil Stall Control

2019 ◽  
Vol 9 (15) ◽  
pp. 2960 ◽  
Author(s):  
Junkyu Kim ◽  
Young Min Park ◽  
Junseong Lee ◽  
Taesoon Kim ◽  
Minwoo Kim ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Flow Separation ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Separation Control ◽  
Angle Effect ◽  
Stall Control ◽  
The Impact

Numerical study on flow separation control is conducted for a stalled airfoil with steady-blowing jet. Stall conditions relevant to a rotorcraft are of interest here. Both static and dynamic stalls are simulated with solving compressible Reynolds-averaged Navier-Stokes equations. It is expected that a jet flow, if it is applied properly, provides additional momentum in the boundary layer which is susceptible to flow separation at high angles of attack. The jet angle can influence on the augmentation of the flow momentum in the boundary layer which helps to delay or suppress the stall. Two distinct jet angles are selected to investigate the impact of the jet angle on the control authority. A tangential jet with a shallow jet angle to the surface is able to provide the additional momentum to the flow, whereas a chord-normal jet with a large jet angle simply averts the external flow. The tangential jet reduces the shape factor of the boundary layer, lowering the susceptibility to the flow separation and delaying both the static and dynamic stalls.

Separation Control of Axial Compressor Cascade by Fluidic-Based Excitations

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Xinqian Zheng ◽  
Yangjun Zhang ◽  
Weidong Xing ◽  
Junyue Zhang
Keyword(s):  
Stokes Equations ◽  
Axial Compressor ◽  
Separated Flow ◽  
Synthetic Jet ◽  
Separation Point ◽  
Navier Stokes ◽  
Separation Control ◽  
Compressor Cascade ◽  
Navier Stokes Equations ◽  
Flow Separation Control

Flow separation control was investigated on a compressor cascade using three types of fluidic-based excitations: steady suction, steady blowing, and synthetic jet. By solving unsteady Reynolds–averaged Navier–Stokes equations, the effect of excitation parameters (amplitude, angle, and location) on performance was addressed. The results show that the separated flow can be controlled by the fluidic-based actuators effectively and the time-averaged performance of the flow field can be improved remarkably. Generally, the improvement can be enhanced when the amplitude of excitation is increased. The optimal direction varies with each type of excitations and is related to physical mechanisms underlying the separation control. For two types of steady excitations, the most effective jet location is at a distance upstream of the time-averaged separation point and the synthetic jet is just at the separation point.

Parametric Study on Aerodynamic Performance of a Centrifugal Fan With Additionally Installed Splitter Blades

2013 ◽  
Author(s):  
Man-Woong Heo ◽  
Jin-Hyuk Kim ◽  
Kyung-Hun Cha ◽  
Kwang-Yong Kim
Keyword(s):  
Flow Separation ◽  
Stokes Equations ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Centrifugal Fan ◽  
Height Ratio ◽  
Navier Stokes Equations ◽  
Fan Performance

Aerodynamic Performance of a centrifugal fan with additionally installed splitter blades in the impeller has been investigated numerically using three-dimensional Reynolds-averaged Navier-Stokes equations. The shear stress transport turbulence model and hexahedral grids system were used to analyze the flow in the centrifugal fan. From results of the flow analysis, considerable energy loss by flow separation was observed in the blade passages. Splitter blades were applied between the main blades to reduce the loss and enhance fan performance. The chord length ratio of splitter to main blade, the angle between splitter and main blade, and the height ratio of outlet and inlet of impeller were selected as the geometric parameters, and their effects on the aerodynamic performance of the centrifugal fan have been investigated. The performance of the centrifugal fan with added splitter blades was improved conspicuously compared to the centrifugal fan without splitter blades. It was found that the installation of splitter blades in the impeller is effective to improve the aerodynamic performance of a centrifugal fan by reducing the flow separation generated between main blades in the impeller.

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